Welcome to the first article in Frank Coyle's series on VoiceXML, an XML technology that is driving many of the phone-based services that you may well be already using. If you've ever called the airlines to check the status of your flight, dialed 1.800.FANDANGO for a movie location, or ordered a pizza from 1.800.DOMINOS, you've already experienced the magic of VoiceXML.

Welcome to the first of a series of articles on VoiceXML, an XML technology
that is driving many of the phone based services that you may well be already
using. If you’ve ever called the airlines to check the status of your
flight, dialed 1.800.FANDANGO for a movie location or ordered a pizza from
1.800.DOMINOS, you’ve already experienced the magic of VoiceXML.

Origins

The origins of VoiceXML go back to 1995, when a team at AT&T Bell Labs began
looking at how to use the Internet to deliver voice applications. The result was
a project called PhoneWeb. When AT&T spun off its Lucent division, a separate
Phone Web project continued at both companies, followed by a third competing
project at Motorola.

In 1998, a W3C conference on voice browsers led to the creation of the
VoiceXML Forum, which was a consortium that included AT&T, Lucent, Motorola and
IBM to coordinate the fragmented phone markup world and to define a standard
dialog design language that developers could use to build conversational
applications. XML was chosen as the basis for the common language, and in 2000
it became a W3C standard, followed by VoiceXML 2.0 in 2004.

When paired with a VoiceXML—compliant voice server, VoiceXML becomes a
powerful, declarative, domain-specific language for speech applications. The
capabilities of VoiceXML include the following:

Synthesized speech (text-to-speech, TTS)

Audio file playback

Recognition of spoken input

Recognition of touchtone input (referred to as DTMF)

Recording of spoken input

Control of dialog flow

Telephony features such as call transfer and disconnect

When integrated with a backend database, VoiceXML can prove to be a powerful
tool in its own right or as a powerful add-on to other services. In a world
where multifaceted web service–based mashups are changing how we think of
application development, VoiceXML brings a compelling voice dimension to the
application service space. Using voice to communicate with the more than 4
billion cell phones expected to be operational by 2010 opens the door to new
ways of delivering personalized customer experiences.